Paralysis on one side of the body can result from stroke, traumatic brain injury, spinal cord injury, or disease. Depending on the nature of the neural damage, it is possible for paralysis patients to recover some degree of motor control. Numerous techniques have been used to facilitate a patient's motor recovery. These include constraint-induced movement therapy, robot-assisted movement, and several methods using neuromuscular electrical stimulation (NMES) of paralyzed muscles.
These techniques also include devices and methods that use permanently implanted electrodes to overcome paralysis. One such device is shown in U.S. Pat. No. 4,799,487, which discloses a device for the re-animation of a paralyzed face. The device includes electrodes implanted in muscles on a healthy side of a face for sensing contractions and sending signals to a processor, which in turn processes these signals and re-transmits them to other electrodes implanted in the counterpart muscles in a paralyzed side of the face to stimulate the counterpart muscles to contract.